Such a communication switching system is already known in the art, e.g. from the article "Architectural Issues in the Interoperability between MANs and the ATM network" by A. Biocca et al., published in the proceedings of the XIII-th International Switching Symposium held in Stockholm from May 27 to Jun. 1, 1990, Session A3, paper #4, volume II page 27.
This known communication switching system includes an Asynchronous Transfer Mode (ATM) switching network whose control modules constitute the control means. An ATM switching network is inherently connection oriented, meaning that before establishing a communication from an origin to a destination a temporary virtual path is established, this path being released at the end of the communication. To be able to establish communications over this network in a connectionless way, i.e. without a virtual path having to be established first, as for instance when transmitting datagrams or broadcast messages and in case of interconnected Local and Metropolitan Area Networks, the known switching system includes a virtual overlay network formed by a plurality of permanently allocated virtual paths with an assigned estimated bandwidth. Communication over these permanent virtual paths which are not released at the end of this communication is done under control of terminal units called connectionless servers which are also part of the virtual overlay network.
A main drawback of this known switching system is that in order to cope with possible traffic variations proper to connectionless traffic, the estimated bandwidth assigned to each of the permanent virtual paths has to be at least equal to the expected peak traffic thereon. This leads to a waste of bandwidth when the real traffic is smaller than the estimated one or to unsatisfactory operation when the real traffic is higher than the estimated one.